Method of making clad metals.



J. B. MONNOT.

METHOD OP MAKING CLAD METALS. APPLICATION FILED AMM, 1910.l

1,110,638. l Patented Sept..15,1914.

A L T \\\1 i "nowto,

. UNITED sTATEs PATENT ernten.

JOHEN' MONNOT, 0F PARIS, FRANCE,

To ah' 1in/om if; may concer-n Be it known that I. Jol-IN F. MoNNo'r, a.

A citizen of the United States, residing at Paris,F rance, have invented certain Methods of Making Clad Metals, of which the following is a specification.

` This invention relates to methods of making clad metals, and it com-prises a process of producing clad metals wherein a, coating metal is fused and maintained in a molten condition beneath a fusedcovcr of a mineral material comprising a halogen compound.

and while so 'molten is employed for coating iron or steel or other ferrous metal; all as more fully hereinafter "described and as claimed.

- In themanufacture of coated metals com-y -prising a steel or iron base 'firmly and'permanently united -by a true metallic union with a coating-of an unlike high melting metal, such as copper, it is necessary that thel two metals be contacted in a clean state and with one metal molten so as to produce a wetting or absolute contact therebetween. This absolute metallic contact, however, it is diliicult to produce in practice, partly because of the free oxiclizability of both metals and partly because of the difficulty of wholly obviating the presence of absorbed air or gases which operate to space apart the metals to be' united. \In a prior application, Sr.No. 281,680, (renewed as application Ser. No. 545,712; Patent No. 971,136, Sept. 27, 1910) whereof the present application is a continuation in part, I have pointed out sundry waysof obviating-these diiiiculties; one such way being to perform the heating of the metal beneath a layer of a fused slag or flux which while acting as a heat-1mparting .or 40.

conducting body in the heating prevents ac- LVcess.of air to the hot meta-l and acts-toshield it. Byheating a billet or other body .of solid iron or steel beneath such a layer vof slag or iux, it may be raised to any' desired ,temperature and when withdrawn throughthe overlying fused 'material it emerges covered with a clinging layer of such flux which op'- I' erates to shield it against contactwith the atmosphere and hence against impairment ofthe metallic surface by oxidation. Upon vnowmdipping this flux coveredfbillet Ain molten copper o-r other suitable molten coating metal which has been similarly heatedl to an appropriateandhigh temperature, the

clinging uX layer is wiped 'oft' progressively l y AssIGNoRTo DUPLEX METALS GMPANY,` OF NEW vom; N. Y., A CORPORATION oF NEW YORK. v

.METHOD or MAKING CLAD is/inTALsi Specification of Letters Patent. Patented Sept, 15 1914b Application led April 2', 1910. Serial No. 553,049. I

as the-billet descends in the molten metal, giving an opportunity for the two metals to contact in an absolute manner` Wit-hout the presence of intervenmg air or .gases or oxld.

All fluxes are of course very much lighter In making copper clad steel under the I .present invention, the molten copper is maintained ata temperature above the melting or ordinary casting temperature Where- 41n it assumes a peculiar co-ndition which I have called, for the lack of another name, they supermolten condition, in which it displays a strong tendency to unite Wit-h iron and steel, Aalloying therewith and readily forming coatings which are united with the base, with a union which is, or is equivalent to, a weld union. Clean steel dipped'mto supermolten copper and then withdrawn is found covered with a clinging film OfCOP- per or copper iron alloy with which a substantial coating of copper can readily be united by casting thereagainst molten copper at a more convenient casting temperature. The joined Ametals so produced may be T0116@ drawn and otherwise worked with the same facility as a billet of either metal and the union persists through the coextension. And the union. so produced is ind1sseverable by the action of cleaving tools,

such as a cold chisel, by heating and quenchy ing, etc.

In the productionof the molten bath vof coating metal, it is convenient also to heat itv beneath a covering layer of molten linx or jslag, as this is' similarly operative in excludiing air or gas and in vpreventing oxidation; giving such molten metal a.metallic surface with .which the dipped billet can readily contact to produce the desired type offunion. On dipping a flux clad billet, the flux wiped off by the molten coating metal simply joins 'this'fioating layer. With this Heating layer v*of ViuXabove thecoating metal, as pointed out'in the said vprior application, ano-ther convenient result follows in that the copper ilmedfbilletfasv it is withdrawn from the molten coating metal andA passes upward through the molterniiux picks-up another clingingA layer ofthe latter which is conthin layer 4 of venient and effective inpreventing cont-act of air with the sensitive surface of the hot filmed billet. If means fwe're not taken to prevent contact of air with the relatively copper upon the billet, such layer being, under the describedA circumstances, substantially only the thickness of molten metal which will cling capillarily, this coating would be oxidized, and so might disappear or might be so far converted into oxid as to hampensubsequent attachment of vr].`his floating layer of if the hot liquid be covered with another filmed steel surface. molten flux above the molten coating metal has a further convenience where such metal contains Volamore copper to the tilizable constituents such as the zinc vof.

ordinary brass, in that it tends to prevent volatilization of such constituents and thereby a. change in the composition of such coatv ing metal.

With any liquid maintained at a-ntemperature below its boiling point, the amount of vaporization in a time unit is proportional to the free' surface exposed and the concentration or partial pressure of the Vapor m thespace above such free surface. Ang

lighter immiscible liquid, as in' coveringhot waterwith oil, the amount of. evaporation ,in-atime unit may be very much lessened;

this being due to the .fact that no free surmetal. For this purpose way face can be exposed and that there is no free space into which the vapor .can expand. These conditions -obtain in melting and malntaining brass and similar alloys beneath a cover o'f molten flux; a {iux being 'an immiscible fluid so far as melted metal is concerned. Under a coating of molten flux, zine can be readily melted and raised nearly to its boiling point without much loss of v the covering layer should be fairly deep. With suchv a ldeep layer ofmolten flux, 'on pouring ymolten metal therethroughl the drops are cleaned ofoxids, scale and other impurities, as Well as of absorbed air, and reach the bottom of `thecontainer as clean-surfaced metal. In a the cleansing action is the same as that involved in pouring ymercury through a deep layer of dilute acid. -In making brass for instance the correct amount of zinc may be poured o r dropped through a deep layer of molten ux in a suitable mold or crucible and then molten copper poured through such flux. Ihe heat; of the .molten copper,

l#which ordinarily volat-ilizev a considerable amount of zinc, does not here do so, owing 'to the protective action of the layer of flux.

The whole operation of producingl clad metals may conveniently be done under a I layer of .molten flux or slag, steel or iron to be coated being heated in a rlayer of molten ux, w1thdrawn therefrom, covered with a clingm' layer of ux to protect it, dipped a-layer of-'molten flux resting on atures.

. freely a body of molten coating metal (such las I brass vwhich has beenformed or melted under Vcover of such flux, as previously described) into such coating metal, withdrawn therefrom, coveredor brazed with a clinging filmed layer of coating metal coveredas it passes, through the flux layer' of iux and then further treated. Such a jacketing.

a film coated billet may, lfor example, next be placed in anothervessel ofjflu'x analcopmolten inorganic non-metallic material -will ordinary `casting temi to proximity -to the In this casting operation do for the flux, since all the silicates, bo-rates and the like, are practically indifferent toward metals of the classes -herein contemplated and since theyare all light which readily oat on molten metal. In so bodiesV ioating on the molten metal, they havean important advantage in the present invention'in that beingrelatively poor conductors of heat they allow the metal thereunder to be raised to comparatively high temper# instance have-the underlying copper in a supermolten condition while the top layers of slag or flux are at a temperature much be-` low. The iux acts as a heat-retaining floating jacket. Borates, such as borax, calcium borate, and the like, silicates, such as the ordinary slags, waterglass, etc., are all suitable substances. combinations of boric acid andsilica with light metals, is notreducible by the heavy L metals, so that these compounds may be used with copper and\iron. Being, however, acid in their nature in a fused state, they readily dissolve the oxids of the heavy metals and this cleansing action is impor.-

' tant in their use. For'the present purposes,

however, it is preferred to use another class of molten inorganic materials, namely, the halogen compounds. -The halogen 'compounds of the light more fusible than corresponding compounds containing oxygen, sothat they allow Work A crucible full of coppermay for- The base in all the ordinary p l metals areall much at a lower temperature. l They are/also more,

fluid than the silicates and borates. Salt (NaCl) for instance melts at 820, C., calcium chlorid at 780 C.

and cuprous-l `chlorid as 1 owl as 410=G. While calcium liiuorid by 1tself=-meltsat a comparativelyhilgh temperature, admXture-'ofit with ot er halogen saltsfand .with silicatesiand i borates lowers its melting'point"'veryfii'nuch.,-

The lsame i'strue of cryolite. The fluorincontaining halogen salts therefore, may very advantageously be used in, connectionl with ratus adapted for the carrying out of the ing the waste gases from the furnace. '8 is a described proces/s.

In the drawing, element 1 is a heating furnace, 2 is' a heating bath filled with flux,

3, andai is a similar heating vessel contain ingf'a layer of molten metal 5 covered by a fioating layer of fiuX 6. 7 is a stack carrybillet of iron or steel to be coated carried by hoisting mechanism 9 and adapted. to be moved from place to place by conveyer ymeans 10. 11 is a mold shown as containing a Alayer of molten flux 12 and a filmed billet 8. V

In the use of the described appara-tus, the

heat of the furnace melts and maintainsthe fiuX in the first heating vessel vin amolten condition. A billet is lowered into the molten material and there retained until it acquires a suitable heat, which' maybe red or yellon7 heat. In the second-heating vessel the flux is made molten by the heat from the furnace and metal melted thereunder. Such metal may be `copper or silver, or other suitable non-ferrous high-melting coating metal, or it may be an alloy such as brass, bronze, etc. This metal may be simply dropped through the layer of molten fiux as pleces or chunks, which then melt in the Crucible 4, under cover of the molten flux, so that the metal-in melting, and thereafter, is absolutely protected from contactwith the atmosphere and it is clean surfaced and pure if originally so or, if the coating metal be an alloy, such as brass, such alloy may be 4formed by melting its ingredients under cover of the layer of molten fluX, as above described. A lbillet withdrawn from the flux is plunged down through the top layer of flux in the second Crucible into the molten metal where it remains until a coating is formed; which ordinarily requires but a few seconds.- In passing down through the flux into the molten metal this covering layer of flux is removed and joins that in the dipping bath. After the billet has become film coated it. is drawn upward through the flux layer where it picks up another clinging coating to protect the delicate, newly-formed film coating. This flux-coated filmed billet may now be transported to the final coating vessel, or mold 11, submerged in the flux therein contained, and molten coating metal poured against it or about it, the molten metal displacing'the flux upward as it de- `scends into the mold, or the molten metal` and thenth'e film-coated, flux covered billet may be lowered into the mold, ldisplacing the molten metal and causing it to 'fillthe fmold. In all these operations it is desirable that the flux employed be substantially the same since obviously flux from-fthe preliminary fluxheating body isconstantly passing mold, and protected by a covering of flux,

to the dipping bath and flux from the dip# ping bath to the final coating bath. The

flux which 1overflows from the final coating lbath may be returned'to heating bath.

The crucibles containing themolten metal and the flux may be of any neutral indifferent material', such as ordinary graphite, or may be the special material of my Patent No. 928,470. y In'my Patent. No. 944,371', dated .Decemthe original flux or 'ber 28, 1909 (application filedJuly16, 1908) I have described and claimed the forming of alloys by melting the constituents, or one or more of the constituents7 thereof, under a deep layer of molten-covering material, and therebygreducing-loss of volatilizable constituents.

As is well known, potassium chlorid (KCl) is a-substantial chemicaliequivalent of sodium chlorid, 4oneof the materials -above named, for use as a protecting flux, and I regard the use of potassiumchlorid, in lieu of sodium chlorid, l vfor such purpose, as within my invention.

Potassium chlorid for all present purposes works like sodium chlorid but it is more expensive and there is no special advantage in its use alone. In admixture with sodium chlorid, however, it produces fluxes melting at a lower temperaturevthan.either.

.What I claim is 1. The process of protecting molten metals .consisting in first. reducing a suitable halogen salt to a fluid condition by heat and then reducing thev metal to be protected to a fluid condition by heat beneath the surface of said halogen salts.

2. The method'of plating ironl or steel, l

cast or -malle'able, consisting in first reducing in a suitable crucible a suitable halogen salt to a fiuid state by heat, then reducing below the surface of said salt the metal or metals to form a bath to a fiuid condition -by heat and protecting the same beneath the surface of vthe halogen salt and then im- .mersing the metal to be plated first through 'l the halogen salt into the said metal bath, and from the metalbath through the halogen salt to the atmosphere, substantially as. set forth.

8. The method of protecting molten metals consisting in first reducing a suitable chlorid to a fluid condition byheat and then reducing the' metal to be protected to a fluid condition by heat beneath the surface ofthe lsaidl chlorid.

iso

4. The method of protecting molten' metals consisting in first reducing chlorild of sodium to a' fiuid condition by heat, and

then 'reducing the metal to be protected to a. fiuid condition by heat beneath the surface 10 layer of molten flux, and then immersing the /nietal article to be coated. through such molten flux into the molten metal therebeneath, and then withdrawing lsuch metal article through the molten flux to the at- 15 JNmosphere, the film of flux adhering to the article when so withdrawn protecting the'l metallic lm formed on 'i e surface Aof Said molten metal, and nal'ly casting against the surface 4so molten coating metal. and

ainstl such surface, the protective iiIm of UX, on; the surface against whichv thezmoltenmetal is so cast being 'displaced by thev moltenmetal as it contacts with such surfacef In testimony whereof I aiiix4 my'signature, in the presence of two witnesses.

' JOHN F. MONNOT.

Witnesses:

JACK H. BAKER,

H. C. Colm.

protected a "further 'layer of, ermittingthe molten metal so cast to solidigy article-by.Contact of suc surface with the 

